YDM4 class locomotives was the most successful class of mainline meter-gauge diesel locomotives ever used in Indian Railways. Originally designed by American Locomtoive Company (Alco) developed and extensively produced by Diesel Locomotive Workshop, Varanasi the YDM4 and its variants is still ruling the meter-gauge networks of India & its neighbouring states. These locos have single piece cast steel frame trimounted Co-Co bogies with asymmetrical arrangement of traction motors, 6 cylinders, 4-stroke diesel engine and panel mounted IRAB-1 brake system - air, hand & dynamic brake. DC-DC transmission in contrast to most other locos that were AC-DC.

This locomotive # 6200, built in the year 1968, is the second YDM4 built by DLW and was in use at the meter-gauge section between Mysore & Chamrajanagar. With a total haulage capacity 1350 hp and a maximum speed of 96 kmph this loco is one of the beauties of mg diesels. It finally retired in the year 2014 and resting as a prime exhibit in Mysore Rail museum.